Can't really fault the guy, he did what he thought was best in a very bad situation. If the police weren't there it may have been worse. Lets look at what happened before, guys comes on train and already he had a bad feling, guy starts to act violently with police present. Gavin DeBecker (Gift of Fear) would have suggested that all the signs were there and that moving down the train away from the guys would have been a good idea.